MXPA05001818A

MXPA05001818A - Process for the preparation of flavor or fragrance microcapsules.

Info

Publication number: MXPA05001818A
Application number: MXPA05001818A
Authority: MX
Inventors: Anne Reilly
Original assignee: Firmenich & Cie
Priority date: 2002-08-19
Filing date: 2003-08-12
Publication date: 2005-08-16
Also published as: JP2006511322A; WO2004016345A1; BR0313195A; DE60325061D1; US20050123757A1; EP1531927A1; EP1531927B1; AR040979A1; CN1330409C; US20040032036A1; AU2003253175A1; ATE416029T1; ES2316847T3; CN1674978A

Abstract

The invention relates to a process for preparing microcapsules by coacervation, wherein the cross-linking of a protein is carried out by a plant extract rich in substituted or unsubstituted phenolic compounds.

Description

PROCESS FOR. THE PREPARATION OF FLAVOR OR AROMA MICROCAPSULES FIELD OF THE INVENTION The present invention relates to the flavor and flavor industry. More particularly, it relates to the coacervation process for the preparation of microcapsules that encapsulate a hydrophobic flavor or flavor, the process characterized by the use of a novel forging agent containing a plant extract rich in phenolic compounds. BACKGROUND OF THE INVENTION Encapsulation is a term often used in the food, flavor and flavor industry. The process used to make the encapsulation may include dehydration techniques such as spray drying or drum drying, spray cooling, extrusion, mechanical coating or coacervation. Coacervation, also called aqueous phase separation is a well-known technique for encapsulating hydrophobic liquids. A coacervation process allows to provide microscopic capsules containing oil, the encapsulating material is a hydrophilic colloid in the form of a gel which is impermeable to oil and deposits evenly and densely around the oil as a core. The encapsulated colloid material is a protein that can form a complex with REF .: 161544 another colloid that has an opposite electrical charge. The coacervation process consists essentially of an aqueous protein solution that is manipulated by changing the physicochemical medium (dilution and / or pH adjustment) to result in a phase separation of the protein from the solution to varying degrees according to the molecular weight of the the protein, its isoelectric point and compatibility with solvents. The coacervation process can be "simple" or "complex". The above designation is employed when a single protein is used to form a capsular wall while phase separation occurs. The second term refers to the use of a second non-protein polymer with opposite charge to produce phase separation. The complex coacervation method is frequently practiced in commercial processes and has been well described in the literature. In particular, in the US patents 2,800,457 and 2,800,458 the complex coacervation is described in a very detailed manner. In general, the coacervation process consists of four basic stages: emulsification, coacervation, formation and setting of the wall. Therefore, the dispersion of oil droplets in a solution of at least one colloid material is subject to dissolution or pH adjustment to form capsules containing oil droplets (coacervation). The colloid participates after the formation of the wall and finally sets and is insolubilized to water to a point where the capsules are extremely resistant to heat and humidity. More particularly, the setting consists of a crosslinking of the colloid layer present in the emulsified oil droplets. The cross-linking of a protein, which is carried out with the aim of altering its aqueous solubility is critical in the encapsulation, and conventionally develops with the use of an aldehyde for example formaldehyde or glutaraldehyde. However, these latter compounds present the disadvantage of be toxic, and can not be used in the production of microcapsules that have to be incorporated in food. In particular, glutaraldehyde, which is described as being most widely used in coacervation processes, is a hazardous chemical that can not be used outside the United States. Alternatives of use have been suggested with respect to the aldehydes in the prior art. For example, CA 1,322,133 describes the gelatin crosslinking by an irido compound. On the other hand. J. Soper et al., In US 6,325,951 and US 6,039,901 suggest an enzymatic cross-linking of oil particles encapsulated in protein by complex coacervation. More particularly, these patents describe a process for the preparation of a complex coacervate of oil particles., each of them encapsulated in a protein coating and then an enzymatic reticulate with the collaboration of transglutaminase to provide thermostable micro-articulations. However, this enzymatic approach is expensive, difficult to control from the process point of view and requires very controlled conditions to achieve consistent results. Therefore, there is still a need for an alternative for setting agents, particularly in the food and flavor industry. The invention offers a novel solution for the aforementioned problems by providing a coacervation process which can be complex or simple and which employs as a setting agent, that is, an agent capable of insolubilizing the protein wall, an extract of a plant that It has the distinction of being rich in phenolic compounds. This novel crosslinking agent unexpectedly turned out to be very effective and easy to handle. In addition, it is not subject to any type of restriction from the legal point of view, which is an advantage. US Pat. No. 3,965,033 and US Pat. No. 3,803,045 have disclosed phenolic compounds useful in the coacervation process. However, in the processes described in these patents, these compounds are added in a stage prior to setting and the crosslinking is carried out with conventional setting agents, such as formaldehyde, acetaldehyde or glutaraldehyde. Therefore, no document of the prior art has described to date a coacervation process in which an extract of a plant containing phenolic compounds is used to set a protein wall. Therefore, the process of the present invention provides a novel and effective solution for improving the crosslinking of a coacervation process, and facilitates the preparation of microcapsules which can be used in particular in the food and flavor industry. BRIEF DESCRIPTION OF THE INVENTION The invention relates to the encapsulation process in coacervation, which comprises the basic stages of emulsification or dispersion of a central hydrophobic material in a protein solution, coacervation, wall formation by cooling of the coacervation, setting, and finally agitation. This process is characterized in that the setting stage is carried out by means of a plant extract rich in phenolic compounds. The invention also relates to microcapsules that are produced by this process. These microcapsules have solidified walls of a high molecular weight protein that at least partially surrounds nuclei of hydrophobic material, where the solidified walls are crosslinked by a setting agent containing at least one botanical extract consisting of substituted or unsubstituted compounds. The invention also relates to a method for solubilizing proteins in water by adding at least one plant extract consisting of substituted or unsubstituted phenol compounds to a coacervate based on proteins where the extract is present in a sufficient amount as to forge at least a portion of the coacervate protein and make it insoluble. The invention provides a process for the preparation of microcapsules containing a hydrophobic core material that includes the following steps: a) emulsifying or dispersing a hydrophobic liquid, a solid suspended in a hydrophobic liquid or a solid in a solution of at least one protein high molecular weight; b) subjecting the emulsion or dispersion obtained in step a) to aqueous solution and / or pH adjustment to achieve coacervation; c) cooling the coacervate formed in step b) to allow the formation of the microcapsules; d) at a temperature between 15 and 30 ° C add a setting agent to the coacervate to crosslink the formed wall; and e) stirring the mixture for at least 48 h to complete the crosslinking reaction. This process is characterized in that the setting agent that is used in step d) contains at least one plant extract consisting of substituted or unsubstituted phenolic compounds. By "high molecular weight protein" is meant a protein with a molecular weight of between 40000 and 100000. The terms "core material" refers to hydrophobic liquid materials that are generally encapsulated by coacervation, like solids suspended in a hydrophobic liquid. The plant extract used in the process according to the invention constitutes a novel agent for insolubilizing the protein wall of an encapsulated hydrophobic core material prepared by coacervation. The cross-linking of a protein is critical for the efficiency of the core encapsulated by the protein, in particular for its thermostability. If a protein wall is not cross-linked, the delivery system will not work as desired. The new setting agent which is used in the invention and which consists of at least one plant extract characterized in that it consists of substituted or unsubstituted phenolic compounds, unexpectedly resulted that it effectively cross-linked the protein wall that is formed after the solidification. The delivery systems provided by the system described herein demonstrated a very interesting slow release of the encapsulated core material compared to traditional glutaraldehyde crosslinking systems. In addition, the reticulated walls of the microcapsules have a good degree of thermostability. On the other hand, the novel setting agent that is provided in the present invention has the advantage of not being dangerous for handling, of low cost, does not require conditions of strict control during the process. Other advantages will appear in the description, as in the examples below. The expression "plant extract" refers to a botanical extract, an extract of herbs or even a wood extract. Examples of botanical extracts include, among others, oak bark extract, olive water or cashew nut liquid. The tea extract is another suitable example for the purposes of the invention. All these extracts contain a certain amount of substituted or unsubstituted phenolic compounds, ie phenols, their homologs, or substituted phenols such as, for example, vanillin, quinones or polyphenols. In a particular embodiment of the invention, a plant extract suitable for the crosslinking of the protein wall is used, a liquid smoke also known as pyroligneous acid. This material is originally extracted from wood preferably birch wood. It is described by S. Aretander in Flavor and Fragrance Chemicals, Montelair, New Jersey, 1969, ref. no. 2780, as a flavor ingredient, useful for "flavoring meats, fish and other preserves, and to a lesser extent for flavoring compositions that mimic caramel, caramel with butter, rum, vanilla, etc., in the flavoring of tobacco. of pyrogenic acid is also used in "smoke" flavoring in products such as meats and fish.This extract contains compounds such as guaiacol, 4-methyl guaiacol, 4-ethyl guaiacol, 4-propyl guaiacol, vanillin, 4- (2- own) vanillone, 4- (1-own) vanillone, acetyl vanillone, eugenol, E-isoeugenol, Z-eugenol, siringol, 4-methyl syringol, 4-ethyl siringol, 4-propyl siringol, siringaldehyde, 4- (2-propio) -siringone, 4- (1-propio) -siringone, 4- (2-propenyl) siringol, E-4 (1-propenyl) siringol, Z-4 (1-propenyl) syringol and acetosiringol. In this particular embodiment of the invention, that is to say, where a "smoke" flavor is used as setting agent in the coacervation process, the organoleptic characteristics of the encapsulated hydrophobic center, in particular its taste in the case of flavor oil , sale are not altered. In other words, despite the fact that pyrogenic acid has flavoring properties as mentioned in the reference textbooks, such. like that of S. Arctander, it turned out that the smoke flavor is not perceived in the reticulate of the final release system with the ingredient. This advantage is very unexpected since the liquid smoke is described as very strong and difficult to mask. In another particular embodiment of the invention, the extract of the plant used for the cross-linking of the protein can be used in conjunction with the tannic acid.

In the process according to the invention, the setting agent is used in proportions ranging from 0.5 to 2.8% by weight relative to the weight of the protein used, on a dry weight basis. The process of the invention begins with the emulsification or dispersion of a hydrophobic liquid, a solid suspended in a hydrophobic liquid or a solid, in a protein solution. As mentioned above, the simple and complex coacervation process can be performed within the framework of the present invention. The above method involves the addition of a non-solvent or other chemical that competes with the protein's solubility, resulting in a protein-rich coacervate phase. On the other hand, the complex coacervation process uses the addition of a second polymer solution with opposite charge to neutralize the charges of the protein molecules, resulting in a coacervate with a neutral polymer-polymer complex. The mixture can be made by forming an aqueous solution of proteins, then emulsifying the core material, and mixing the emulsion with an aqueous solution of anionic polymer, or the two solutions can be made and mixed and the core material can then be emulsified. . Any anionic polymer that reacts with the protein can be used to form complex coacervates. In particular, gum arabic, sodium alginate, agar, carrageenan, carboxymethyl cellulose, sodium polyacrylate or polyphosphoric acid are suitable anionic polymers for the purpose of the invention. Both techniques are well known and have been thoroughly described in the prior art, for example, by John C. Soper in "Utílization of Coacervated Flavors", Proceedings of Flavor Symposium, American Society, Chapter 10, 1995. Protein is an essential element in the process of the invention, since it will be subjected to solidification to form a wall around the oil droplets, before setting. The use of proteins for the encapsulation is limited but versatile, due to its solidification and solubility characteristics. These characteristics are manipulated by changes in temperature, pH, addition of a second polyelectrolyte solution, a second solvent or even an ionizing salt solution. The molecular weight of the protein ranges from 40,000 to 100,000. In a particular embodiment of the invention, the protein used in the process is selected from a group including gelatin and albumin. Preferably, gelatin will be used. There is no particular limitation regarding the gelatin that is used but it is preferable to use some type of gelatin that has good physicochemical and chemical properties as typified by the ability to form a film, the nature of the ampholyte, the control of the charges by pH , and the change of solution to gel at a critical temperature Specifically established, any gelatin which complies with the specification for the production of microcapsules can be used More preferably, a gelatin with an isoelectric point of 3.5 to 10 and a Efflorescence resistance of 225 to 325. In one embodiment of the invention, the core material to be encapsulated is a flavor or flavor ingret or flavor composition The terms aroma and ingrets or flavor composition as used in present, they serve to define a variety of materials of natural and synthetic origin, including compounds or mixtures The process of the invention can provide a particular release system for the labile or volatile hydrophobic components in liquid form. In the literature, specific examples of the components can be found, for example, in Fenaroli's Handbook of Flavor Ingret, 1975, CRC Press; Synthetic Food Adjuncts, 1947 by M. B. Jacobs, edited by Van Nostrand or Perfume and Flavor Chemicals of S. Aretander 1969, Montclair, NJ, (USA). These substances are well known to those experienced with the technique of perfumes, flavors and / or flavorings of products, that is, those that impart aroma and / or perfume or flavor to products that are traditionally flavored or perfumed, or that modify the aroma and / or taste of the products. The natural extracts can also be encapsulated in the system of the invention; these include, for example, citrus extracts such as lemon, orange, lime, pineapple, tangerine or coffee oils, tea, mint, cocoa, vanilla or essential oils of herbs and spices, among others. The proportions of the ingredients or hydrophobic compositions range between 35 and 90% by weight in relation to the weight of the protein that is used. The process of the invention is also suitable for the encapsulation of other core materials in addition to the flavoring and flavoring ingredients. It can also be used to prepare the delivery systems for pharmaceutical or cosmetic ingredients. In a second step of the process of the invention, the emulsion or dispersion that is achieved conforms to step a) is subjected to dissolution and / or pH adjustment to achieve coacervation. The first two stages must be carried out at a temperature above the solidification point of the colloid material that is used. The coacervate that is formed is further cooled to a temperature equal to or lower than the solidification point of the protein to provide for the formation of the microcapsule wall. In general, the temperature ranges between 5 and 15 ° C depending on the source of gelatin. The cooling index ranges between 0.25 ° / min. and l ° / min. Then, the botanical agent which is the setting agent is added at a temperature of about 15 to 30 ° C and a pH of 3.5 to 7, and finally it is stirred gently for 48 hours. The components of the extract of the plant in this way react with the wall of the protein and make it insoluble in water. Other characteristics of the process will be specified in the following examples. Variations of the coacervation process described above can be considered within the scope of the invention. In this way, the description of the basic steps of the process of the invention should not be interpreted as limiting the invention, since a person skilled in the art knows well the alternative or particular ways to carry out the process, which will not alter the character of the invention, while using a setting agent as defined above. For example, an optional stage of spray drying of the coacervate can be used to obtain a dry and free-flowing powder. The delivery system obtained by the process described above is also a feature of the present invention. The cross-linking of the protein to alter aqueous solubility is critical in proteins that employ encapsulation. The products obtained according to the present invention, due to the new crosslinking agent, show advantageous release characteristics compared to a classic coacervate crosslinking with glutaraldehyde as shown by the comparative example below. The microcapsules produced by the process of the invention can be used in many types of applications in the field of flavorings and AROMAS. In particular, they can be used for flavoring and confectionery, tobacco, frying and canning applications (thermal processing). On the other hand, in the field of perfumery, they can be used for perfuming different products for the consumer, such as household cleaners, pre-moistened towels and personal care products. Therefore, the flavoring or flavoring compositions comprising the microcapsules according to the invention together with other flavoring or flavoring co-ingredients are also embodiments of the present invention. Finally, another embodiment of the invention relates to a method for insolubilizing proteins in water by adding a plant extract comprising phenolic compounds substituted or unsubstituted to a protein-based coacervate. BRIEF DESCRIPTION OF THE FIGURES Figure 1 (Fig. 1) represents the indices of steam distillation of unencapsulated orange oil and coacervate of orange oil crosslinked with an aqueous glutaraldehyde solution at 0.14% and 50% concentration. Figure 2 (Fig. 2) represents the distillation index of a cross-linked coacervate with 0.28% liquid smoke (Charsol® Supreme; origin: Red Arrow Company LLC, Wisconsin, USA). DETAILED DESCRIPTION OF THE INVENTION The invention will be described in more detail in the following examples, where the temperature is determined. indicates in degrees centigrade and the abbreviations mentioned are the conventional ones. Example 1 Preparation of an orange peel oil release system Cold pressed orange peel was encapsulated by coacervation according to the following formula: Ingredients Grams% dry 275 Bloom gelatin type A 109 20.70 (solution at 8.25%) Gum arabic (solution at 3.85%) 156 29.63 Orange peel oil 60 11.40 Demineralised water 200 37.99 Liquid smoke1 '1.47 0.28 Total 100.00 1) Two were used types of samples: a) Charsol® Supreme (water base, 15-23 mg / ml of smoke components); b) Charoil® Hickory (soybean oil base, 7.3-8.1 mg / ml smoke compounds); origin: Red Arrow Company LLC, isconsin, USA. Procedure for the preparation The gelatin solutions were heated, on the one hand, that of gum arabic, on the other in a water bath at 60 ° C. After complete dissolution, the solutions were cooled to 50 ° C and mixed with stirring and magnetic stirring. The orange peel oil was added, and stirring continued for 1 minute. Water solution (45 ° C) was added and stirring continued. The contents of the beaker were allowed to cool to 15 ° C with continuous stirring. During the cooling period, the development of the coacervation and the coating of the particles was monitored through the microscope. Once finished, when coacervate free protein was no longer observed, liquid smoke was added and the mixture was kept under stirring for 48 h (minimum). The samples were stored at 40 ° C for 24 hours, and then examined under a microscope. The integrity of the wall was monitored by heating at 90 ° C for 15 minutes, and examined under a microscope. Additional samples were prepared using Charsol® Supreme (water-based) at 0.7% and 0.14% in the formulation. These samples were controlled in a similar way.

The results appear in Table 1. Table: Coacervate stored at 40 ° C for 24 h and heated at 90 ° for 15 minutes.

Example 2 Steam distillation in release systems prepared according to Example 1 - Comparison between liquid smoke and gluraraldehyde. Steam distillation was carried out in the sample prepared according to Example 1 containing Charsol® Supreme at 0.28%, to verify the extent of the crosslinking and the release rate. The same experiment was performed with coacervate cross-linked with 0.14% aqueous glutaraldehyde (concentration of the 50% solution). Figures 1 and 2 represent the steam distillation indices for each sample. It can be stated that the rate of release of coacervate cross-linked with aqueous liquid smoke at 0.28% (Charcol® Supreme) is advantageously only one third of a sample cross-linked with 0.14% aqueous glutaraldehyde, as evidenced by the respective slope of the curves of regression. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims

CLAIMS Having described the invention as above, the claim contained in the following claims is claimed as property: 1. A process for the preparation of microcapsules comprising a central hydrophobic material the process consists of the following steps: a) emulsify or disperse a hydrophobic liquid, a solid suspended in a hydrophobic liquid, or a solid in a solution of at least one high molecular weight protein; b) subjecting the emulsion or dispersion obtained in step a) to aqueous solution and / or pH adjustment to achieve coacervation; c) cooling the coacervate formed in step b) for the formation of the walls of the microcapsules; d) adding a setting agent to the coacervate to crosslink the formed wall at a temperature of 15 to 30 ° C; and e) stirring the mixture for at least 48 hours to complete the crosslinking reaction, characterized in that the setting agent used in step d) contains at least one botanical extract consisting of substituted or unsubstituted phenolic compounds.
2. The process according to claim 1, characterized in that the setting agent represents between 0.5 and 2.5% by weight with respect to the weight of the protein, on a dry basis.
3. The process according to claim 1, characterized in that the setting agent contains at least one plant extract selected from the group including botanical extracts, herbal extracts and wood extracts.
4. The process according to claim 3, characterized in that the setting agent contains a concentrated tea extract.
5. The process according to claim 3, characterized in that the setting agent contains pyrogenic acid.
6. The process according to claim 1, characterized in that the hydrophobic core material is a flavoring or flavoring ingredient or composition.
7. The process according to claim 1, characterized in that the protein solution also contains an anionic polymer.
The process according to claim 7, characterized in that the anionic polymer is selected from a group that "includes gum arabic, sodium alginate, agar, carrageenan, carboxymethyl cellulose, sodium polyacrylate and polyphosphoric acid.
9. The process according to claim 1, characterized in that the protein contains gelatin.
10. Microcapsules characterized in that they are capable of being obtained by a process according to claim 1.
11. Microcapsules characterized in that they contain solidified walls of a protein of high molecular weight that at least partially surround nuclei of hydrophobic material, where the solidified walls they are crosslinked by a setting agent containing at least one botanical extract consisting of substituted or unsubstituted phenolic compounds.
The microcapsules according to claim 11, characterized in that the protein is gelatin or albumin and the plant extract is selected from a group that includes botanical extracts, herbal extracts or wood extracts.
13. A method for insolubilizing proteins in water, characterized in that it consists of adding at least one plant extract containing substituted or unsubstituted phenolic compounds to a protein-based coacervate to form a mixture in which the extract is present in a enough to set at least a portion of the coacervate protein to make it insoluble.
14. A method for imparting, improving or modifying the organoleptic properties of a flavoring or flavoring composition, characterized in that it consists of adding to the composition the microcapsules according to claim 10.
15. A flavoring composition or an aromatized article, characterized in that it comprises, together with flavoring co-ingredients, solvents or adjuvants commonly used in perfumery, microcapsules according to claim 10.
16. A flavored article according to claim 15, characterized in that it is in the form of a cleaning product, pre-moistened towel or products for personal hygiene.
17. A flavoring composition or a flavored product, characterized in that it comprises, together with flavoring co-ingredients or adjuvants commonly used in industry, microcapsules according to claim 10.
18. A flavored product according to claim 17, characterized in that It is in the form of a confectionery, tobacco, frying or canning product.